如何判断当前操作系统的版本

//------------------------------------------------------------------------------------------------
//判断操作系统涵数及变量，jingzhou xu
typedef enum tagWin32SysType{
   Windows32s,
   WindowsNT3,
   Windows95,
   Windows98,
   WindowsME,
   WindowsNT4,
   Windows2000,
   WindowsXP
}Win32SysType;

//判断操作系统涵数及变量，jingzhou xu
Win32SysType IsShellSysType()
{
   Win32SysType  ShellType;
   DWORD winVer;
   OSVERSIONINFO *osvi;
   
   winVer=GetVersion();
   if(winVer<0x80000000){/*NT */
      ShellType=WindowsNT3;
      osvi= (OSVERSIONINFO *)malloc(sizeof(OSVERSIONINFO));
      if (osvi!=NULL){
         memset(osvi,0,sizeof(OSVERSIONINFO));
         osvi->dwOSVersionInfoSize=sizeof(OSVERSIONINFO);
         GetVersionEx(osvi);
         if(osvi->dwMajorVersion==4L)ShellType=WindowsNT4;
         else if(osvi->dwMajorVersion==5L&&osvi->dwMinorVersion==0L)ShellType=Windows2000;
         else if(osvi->dwMajorVersion==5L&&osvi->dwMinorVersion==1L)ShellType=WindowsXP;
         free(osvi);
      }
   }
   else if  (LOBYTE(LOWORD(winVer))<4)
      ShellType=Windows32s;
   else{
      ShellType=Windows95;
      osvi= (OSVERSIONINFO *)malloc(sizeof(OSVERSIONINFO));
      if (osvi!=NULL){
         memset(osvi,0,sizeof(OSVERSIONINFO));
         osvi->dwOSVersionInfoSize=sizeof(OSVERSIONINFO);
         GetVersionEx(osvi);
         if(osvi->dwMajorVersion==4L&&osvi->dwMinorVersion==10L)ShellType=Windows98;
         else if(osvi->dwMajorVersion==4L&&osvi->dwMinorVersion==90L)ShellType=WindowsME;
         free(osvi);
      }
   }

   return ShellType;
}
//------------------------------------------------------------------------------------------------

用法　：
    //Win98、95、32下不用,jingzhou xu
   Win32SysType SysType = IsShellSysType();
   if(SysType != Windows32s && SysType != Windows95 && SysType !=Windows98)
   {
      //显示动态GIF图像logo,jingzhou xu
      if (m_Picture.Load(MAKEINTRESOURCE(IDR_GIF),_T("GIF")))
      {
         m_Picture.Draw();   
      }
   }